Molecular Interpretation of the $P_c(4440)$ and $P_c(4457)$ States

Understand

A molecular model of the $P_c(4457)$ and $P_c(4440)$ LHCb states is proposed.

• The model relies on channels coupled by long range pion-exchange dynamics with features that depend crucially on the novel addition of the $\Lambda_c(2595)\bar D$ channel.
• A striking prediction of the model is the unusual combination of quantum numbers $J^P(4457) = 1/2^+$ and $J^P(4440) = 3/2^-$.
• Unlike in other models, a simultaneous description of both states is achieved without introducing additional short-range interactions.